The neural retina develops from an epithelia of undifferentiated cells into a stratified structure with a highly organized appearance and several different types of cells. While there is a great deal of morphological and physiological information about the mature retina, very little is known about the cellular interactions and biochemical events that result in the retina's normal development. One of the major reasons for this is that techniques that allow identification of specific cell types and the purification of these populations have not been available. As a result, many in vivo and in vitro experiments designed to address developmental quesitons are presently impossible to perform or interpret. We have developed a number of monoclonal antibodies that bind to specific classes of cells in the chick retina, including ganglion cells, amacrine cells, photoreceptors, and Muller cells. One of our goals is characterize the cell specific antigens defined by these antibodies using both morphological and biochemical techniques. We also propose to use recently develop0ed approaches to produce antibodies specific for bipolar cells and horizontal cells. Finally, these antibodies will be used in in vitro experiments to study how cell-cell interactions and various types of substrates ionfluence the differentiation of specific classes of cells in the retina.